31032331021 has 4 divisors (see below), whose sum is σ = 31033702044. Its totient is φ = 31030960000.

The previous prime is 31032331007. The next prime is 31032331051. The reversal of 31032331021 is 12013323013.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12013323013 = 23143 ⋅519091.

It can be written as a sum of positive squares in 2 ways, for example, as 19820697796 + 11211633225 = 140786^2 + 105885^2 .

It is a cyclic number.

It is not a de Polignac number, because 31032331021 - 2²⁹ = 30495460109 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31032331021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31032331051) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 650980 + ... + 697021.

It is an arithmetic number, because the mean of its divisors is an integer number (7758425511).

Almost surely, 2^31032331021 is an apocalyptic number.

It is an amenable number.

31032331021 is a deficient number, since it is larger than the sum of its proper divisors (1371023).

31032331021 is a wasteful number, since it uses less digits than its factorization.

31032331021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1371022.

The product of its (nonzero) digits is 324, while the sum is 19.

Adding to 31032331021 its reverse (12013323013), we get a palindrome (43045654034).

The spelling of 31032331021 in words is "thirty-one billion, thirty-two million, three hundred thirty-one thousand, twenty-one".